<!DOCTYPE html>
<html lang="zh-cn">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style>
		.a{
			width: 100%;
			height:200px;
			background: red url() 0 0 no-repeat;
		}

		.b{
			width: 60%;
			height: 200px;
			float: left;
			background: blue url() 0 0 no-repeat;
		}
		.c{
			width:35%;
			height: 200px;
			float: right;
			background: gray url() 0 0 no-repeat;
		}
	</style>
</head>
<body>
	<div class="a">
		<div class="b"></div>
		<div class="c"></div>
	</div>
</body>
</html>